55500009991 has 2 divisors, whose sum is σ = 55500009992. Its totient is φ = 55500009990.

The previous prime is 55500009937. The next prime is 55500010057. The reversal of 55500009991 is 19990000555.

It is a happy number.

55500009991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 55500009991 - 2⁷ = 55500009863 is a prime.

It is a super-2 number, since 2×55500009991² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55500009391) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27750004995 + 27750004996.

It is an arithmetic number, because the mean of its divisors is an integer number (27750004996).

Almost surely, 2^55500009991 is an apocalyptic number.

55500009991 is a deficient number, since it is larger than the sum of its proper divisors (1).

55500009991 is an equidigital number, since it uses as much as digits as its factorization.

55500009991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 91125, while the sum is 43.

The spelling of 55500009991 in words is "fifty-five billion, five hundred million, nine thousand, nine hundred ninety-one".